Can we use same record on level zero and level 1 as primary record?

Question: Can we use same record on level zero and level 1 and on both levels it is being used as primary record?
Answer is Yes. Hold on.... We have a condition here.

If we have effective date as one of the keys and all the fields after Effective date are being used in Level 1 then we can use same record on level zero and level 1 and on both levels it is can be used as primary record.

Otherwise, with other keys, it will not serve any purpose, though it is technically feasible.